Measurements of occupational ultraviolet exposure and the implications of timetabled yard duty for school teachers in Queensland, Australia: Preliminary results

Abstract

Simultaneous personal measurements of the occupational ultraviolet exposure weighted to the International Commission on Non-Ionising Radiation Protection hazard sensitivity spectrum (UVICNIRP) were made over a five week period (44 person-days) in the second half of the summer school term of 2012 in Queensland, Australia for individual high school teachers located at latitudes of 27.5°S and 23.5°S. These teachers were employed for the duration of the study in a predominately indoor classroom teaching role, excluding mandatory periods of lunch time yard duty and school sport supervisions. Data is presented from personal measurements made to the shirt collar using polyphenylene oxide (PPO) film UV dosimeters. UVICNIRP exposure data is presented for each week of the study period for the shirt collar measurement site and are further expressed relative to the measured ambient horizontal plane exposure. Personal exposures were correlated with time outdoors, showing a higher exposure trend on days when teachers were required to supervise outdoor areas for more than 2h per week (mean daily exposure: 168Jm−2UVICNIRP±5Jm−2 (1σ)) compared to the study average (mean daily exposure: 115Jm−2UVICNIRP±91Jm−2 (1σ)). Time spent in an open playground environment was found to be the most critical factor influencing the occupational UVICNIRP exposure. A linear model was developed showing a correlation (R2=0.77) between the time teachers spent on yard duty and UVICNIRP exposure, expressed relative to ambient. The research findings indicate a greater reduction in personal exposure can be achieved by timetabling for yard duty periods in playground areas which offer more shade from trees and surrounding buildings. All mean daily personal exposures measured at the shirt collar site were higher than the ICNIRP occupational daily exposure limit of 30Jm−2 for outdoor workers.